ActiveX, Javascript, and unsafe C# code

The javascript error you are seeing indicates that the callme() method is not found on the object SPW...I agree

I'll add the test and get back to you

So you have built a DLL in C# and have exported a COM interface?  Not sure what you mean by export Comm Interface.

Is it essential that you use pointers?  The code that is contained within the DLL uses pointers...Is it possible to use the COM Interop functions to marshall the pointers? Dunno, not familar with this interested to learn

If you're not using a COM interface on a .NET component, then it probably is a client security issue.  By default, "Allow Calls to Unmanaged Code" is set to No for assemblies in the Intranet and Internet zones.  This is set on each client in the Control Panel under .Net Framework Configuration.  If you use Active Directory, the settings can be pushed out at the enterprise level.

Are the calls to unmanaged code Windows API calls?

Your question title has ActiveX in it, which is why I originally asked about exposing a Component Object Model (COM) interface.  I don't think that is what you're actually doing.  Which is fine.

Take a look at this link that describes how to request permission to run unsafe code.  Note that the client still needs to provide that permission via the method above.
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/csref/html/vcwlkSecurityTutorial.asp

The interesting part:
private static void CallUnmanagedCodeWithPermission()
    {
        // Create a security permission object to describe the
        // UnmanagedCode permission:
        SecurityPermission perm =
           new SecurityPermission(SecurityPermissionFlag.UnmanagedCode);

        // Check that you have permission to access unmanaged code.
        // If you don't have permission to access unmanaged code, then
        // this call will throw a SecurityException.
        // Even though the CallUnmanagedCodeWithPermission method
        // is called from a stack frame that already
        // calls Assert for unmanaged code, you still cannot call native
        // code. Because you use Deny here, the permission gets
        // overwritten.
        perm.Assert();

        try
        {
            Console.WriteLine("Attempting to call unmanaged code with permission.");
            NativeMethods.puts("Hello World!");
            NativeMethods._flushall();
            Console.WriteLine("Called unmanaged code with permission.");
        }
        catch (SecurityException)
        {
            Console.WriteLine("Caught Security Exception attempting to call unmanaged code. Whoops!");
        }
    }

Ok, I added the following call if (!SPW) alert("ActiveX component not installed")
and the alert window never pops up...so, I read the security article and tried it
<script type="text/javascript">      
function callMe() {
                if( !SPW )
                    alert("ActiveX component not installed");
                document.getElementById("TextBox1").innerText = SPW.callme();
            }                               
        </script>
...the thing is  

...the this is, is that SPW.callme never gets invoked